Oil Fired Boiler Ratings & Brand Comparison
Expert Overview:
- With our oil fired boiler ratings, you can compare boiler models side by side using our Head To Head tool.
- You can compare 39 models from 24 brands brands in ten categories such as warranty, efficiency, construction, availability, & where they are made.
- You can also read the individual reviews of each brand below.
Quick Reference: Oil Fired Boiler Comparison Categories
| Category | What We Compare |
|---|---|
| Brand | The manufacturer of the oil-fired boiler. |
| Model | The specific oil-fired boiler model or series. |
| Efficiency | AFUE efficiency rating where provided. |
| Condensing | Whether the boiler uses condensing or non-condensing technology. |
| Wall Mounted | Whether the boiler is designed for wall-mounted installation. |
| Two Stage Burn | Whether two-stage burner operation is available. |
| Modulating Control | Whether modulating burner/control operation is available. |
| Parts Warranty | Warranty coverage for parts and controls. |
| Heat Exchanger Warranty | Warranty coverage for the boiler heat exchanger. |
| Dealer Required | Whether professional dealer distribution is required. |
| Factory Location | Where the boiler is manufactured. |
Oil Fired Boiler Head To Head Comparison
Select two oil fired boiler brands below to compare their available specifications side by side.
| Select Boiler | ||
|---|---|---|
| Brand | N/A | N/A |
| Model | N/A | N/A |
| Efficiency | N/A | N/A |
| Condensing | N/A | N/A |
| Wall Mounted | N/A | N/A |
| Two Stage Burn | N/A | N/A |
| Modulating Control | N/A | N/A |
| Parts Warranty | N/A | N/A |
| Heat Exchanger Warranty | N/A | N/A |
| Dealer Required | N/A | N/A |
| Factory Location | N/A | N/A |
Oil Fired Boiler Video Comparison
Select two oil fired boiler brands to find a comparison video on the HVAC Repair Guy YouTube channel.
Oil Fired Boiler Brand Reviews
Benjamin
★★★★☆Benjamin Heating Products manufactures oil-fired boilers in Canada and offers the Multi-Temp series for residential hydronic heating. The Multi-Temp provides up to 86.7% AFUE efficiency, uses a cast iron heat exchanger, and supports both conventional chimney and direct-vent installation. The boiler is designed for easy service access and offers a 20-year limited heat exchanger warranty. Benjamin is a strong choice for homeowners looking for a durable, serviceable Canadian-made oil boiler.
AFUE Efficiency
Benjamin Multi-Temp oil boilers provide up to approximately 86.7% AFUE efficiency, placing them among the more efficient conventional oil-fired boilers.
Condensing vs Non-Condensing
The Multi-Temp is a conventional non-condensing oil boiler designed for standard high-temperature hydronic heating systems.
Heat Exchanger Design
Constructed with a durable cast iron heat exchanger engineered for long service life and reliable heat transfer.
Venting Options
Supports both conventional chimney venting and direct-vent configurations depending on the selected installation arrangement.
Warranty
Benjamin provides a 20-year limited warranty on the heat exchanger, with additional coverage for components depending on the model and installation.
Controls
Uses conventional burner and operating controls appropriate for residential hydronic heating applications.
Serviceability
Designed with technician access and service-friendly construction to simplify annual cleaning and maintenance.
Benjamin Oil Fired Boiler Model Comparison
Premium Series: Multi-Temp
Why choose it: Canadian manufacturing, cast iron construction, up to 86.7% AFUE
efficiency, direct-vent capability, and strong heat exchanger warranty coverage.
Trade-offs: Non-condensing design, floor-mounted configuration, and
availability through a more limited distribution network than the largest U.S. brands.
Bryant
★★★☆☆Bryant offers oil-fired boiler products through its broader heating equipment distribution network. The brand provides conventional cast iron oil boiler technology intended for residential hydronic heating. Bryant equipment benefits from established contractor support and parts availability, although the oil boiler lineup is less prominent than its gas and heat pump products.
AFUE Efficiency
Bryant oil boiler efficiency varies by model and configuration, with conventional non-condensing equipment designed to meet applicable residential efficiency requirements.
Condensing vs Non-Condensing
The reviewed Bryant oil boiler equipment uses conventional non-condensing technology.
Heat Exchanger Design
Uses cast iron heat exchanger construction intended for durability and long-term residential heating service.
Venting Options
Conventional venting is used on the reviewed oil-fired boiler configurations, subject to installation requirements.
Warranty
Warranty coverage depends upon the specific model, installation, and applicable Bryant terms.
Controls
Conventional burner and operating controls are used for residential hydronic heating.
Serviceability
Standard access arrangements allow technicians to perform routine burner service, cleaning, and inspection.
Bryant Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Established contractor network, conventional cast iron
construction, and familiar service technology.
Trade-offs: Oil boilers are not the primary focus of the Bryant product lineup,
and model availability can vary by market.
Buderus
★★★★☆Buderus oil-fired boilers are known for durable cast iron construction, efficient heat transfer, and professional-grade hydronic heating design. The G215 series, for example, uses a three-pass cast iron heat exchanger and can achieve high conventional oil boiler efficiency. Buderus products are generally distributed through professional heating contractors and are respected for their serviceability and long operating life.
AFUE Efficiency
Selected Buderus oil boiler models provide efficiency in the mid-to-upper 80% AFUE range.
Condensing vs Non-Condensing
Buderus oil boilers reviewed here use conventional non-condensing operation.
Heat Exchanger Design
The cast iron heat exchanger uses multi-pass heat transfer paths designed to extract substantial heat from combustion gases.
Venting Options
Venting configurations depend on the specific model and installation, with conventional chimney applications common.
Warranty
Buderus provides substantial limited warranty coverage for qualifying cast iron heat exchangers, subject to its published warranty terms.
Controls
Professional-grade burner and hydronic controls support reliable operation and system management.
Serviceability
Service access is designed around professional boiler maintenance, including cleaning of heat transfer surfaces and burner components.
Buderus Oil Fired Boiler Model Comparison
Premium Series: G215
Why choose it: Three-pass cast iron heat exchanger, strong efficiency for a
conventional oil boiler, durable construction, and professional contractor support.
Trade-offs: Non-condensing technology, floor-mounted design, and professional
distribution requirements.
Carrier
★★★★☆Carrier oil-fired boilers provide conventional hydronic heating technology backed by a large HVAC distribution and contractor network. The brand's oil boiler products use cast iron heat exchangers and conventional burner systems. Carrier's major advantage is the broad availability of qualified service technicians and replacement components in markets where the oil boiler lineup is supported.
AFUE Efficiency
Carrier oil-fired boiler efficiency varies by model, with conventional models generally operating in the mid-80% AFUE range.
Condensing vs Non-Condensing
The reviewed Carrier oil boiler products are non-condensing designs.
Heat Exchanger Design
Cast iron sectional heat exchangers provide durable heat transfer and long-term service capability.
Venting Options
Conventional venting is supported on the reviewed configurations, subject to local installation requirements.
Warranty
Warranty coverage varies by model and may include separate provisions for heat exchanger and other components.
Controls
Standard burner and operating controls are used to provide safe and reliable hydronic heating operation.
Serviceability
Carrier's broad contractor network can make routine maintenance and replacement component sourcing easier in supported markets.
Carrier Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Large contractor network, familiar HVAC service infrastructure,
and conventional cast iron boiler technology.
Trade-offs: Availability of specific oil boiler models depends heavily on
geographic market and distributor support.
Conforto
★★★☆☆Conforto manufactures oil-fired heating equipment for residential applications, with products focused on conventional hydronic heating. Its boilers use cast iron construction and conventional burner technology. Conforto can be attractive where local dealer support is strong, but distribution and service availability should be considered before selecting the brand.
AFUE Efficiency
Conforto oil boilers provide conventional efficiency levels appropriate for residential oil-fired hydronic heating.
Condensing vs Non-Condensing
The reviewed Conforto boilers use non-condensing technology.
Heat Exchanger Design
Cast iron sectional construction provides durability and reliable heat transfer.
Venting Options
Conventional venting is used for the reviewed equipment.
Warranty
Warranty coverage depends on the individual model and the applicable manufacturer terms.
Controls
Conventional oil burner and operating controls are used for residential applications.
Serviceability
Standard service access allows technicians to clean and maintain the boiler and burner assembly.
Conforto Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Conventional cast iron construction and straightforward oil
boiler technology.
Trade-offs: Dealer and parts availability should be verified locally before
purchase.
De Dietrich
★★★☆☆De Dietrich offers European-designed heating equipment with a long history of cast iron boiler manufacturing. Its oil-fired products emphasize durable heat exchanger construction and efficient heat transfer. The brand can be a good choice when supported by an experienced local distributor, but availability and service infrastructure vary by region.
AFUE Efficiency
De Dietrich oil-fired boilers provide conventional efficiency appropriate for residential hydronic heating.
Condensing vs Non-Condensing
The reviewed oil boiler products use conventional non-condensing operation.
Heat Exchanger Design
Cast iron heat exchanger construction provides durability and long-term thermal performance.
Venting Options
Venting requirements depend on the model and installation configuration.
Warranty
Warranty coverage varies by product and local distribution terms.
Controls
Conventional burner and boiler operating controls are used on the reviewed equipment.
Serviceability
Service access supports normal annual cleaning and burner maintenance procedures.
De Dietrich Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Long history of boiler manufacturing and durable cast iron
construction.
Trade-offs: Local availability and qualified service support should be
confirmed before installation.
Dunkirk
★★★☆☆Dunkirk manufactures residential heating equipment including oil-fired boilers. The brand focuses on straightforward, serviceable boiler designs using cast iron heat exchangers and conventional oil burners. Dunkirk can offer good value for homeowners who prioritize proven technology and local contractor support over advanced controls.
AFUE Efficiency
Dunkirk oil boiler efficiency is generally in the conventional mid-80% AFUE range depending on model.
Condensing vs Non-Condensing
The reviewed Dunkirk oil-fired boilers use non-condensing technology.
Heat Exchanger Design
Cast iron sectional heat exchangers are designed for durability and long service life.
Venting Options
Conventional chimney venting is used on many of the reviewed configurations.
Warranty
Warranty terms vary by model, with heat exchanger coverage typically exceeding standard component coverage.
Controls
Conventional burner and safety controls provide straightforward operation.
Serviceability
Simple construction and conventional access make routine cleaning and burner service familiar to heating technicians.
Dunkirk Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Straightforward cast iron construction, familiar service
procedures, and established distributor support.
Trade-offs: Conventional efficiency and limited advanced control features
compared with premium equipment.
Lennox
★★★★☆Lennox offers residential oil-fired boiler equipment through its extensive HVAC dealer network. The brand's oil boiler products use conventional cast iron construction and oil burner technology, providing reliable hydronic heating with contractor support. Lennox is particularly attractive where a strong local Lennox dealer is available.
AFUE Efficiency
Lennox oil-fired boiler efficiency varies by model and configuration, generally providing conventional mid-to-high 80% AFUE performance.
Condensing vs Non-Condensing
The reviewed Lennox oil boiler equipment is non-condensing.
Heat Exchanger Design
Durable cast iron heat exchanger construction provides long-term service capability.
Venting Options
Venting configurations depend on the boiler model and installation requirements.
Warranty
Warranty provisions vary by model and may provide separate heat exchanger and component coverage.
Controls
Conventional operating and burner controls provide dependable residential operation.
Serviceability
Lennox dealer support provides access to trained technicians familiar with the brand's heating equipment.
Lennox Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Strong contractor network, established parts infrastructure, and
conventional cast iron boiler construction.
Trade-offs: Oil boiler availability varies by market and is less prominent than
Lennox's gas furnace and heat pump offerings.
NTI
★★★★☆NTI is known primarily for high-efficiency hydronic heating equipment, including advanced boiler technology. Its oil-fired offerings, where available, emphasize efficient heat transfer and professional installation. NTI's reputation for modern boiler design makes it a strong consideration where local dealer and service support are available.
AFUE Efficiency
NTI equipment is designed around efficient hydronic heating, although exact efficiency depends on the specific oil-fired model.
Condensing vs Non-Condensing
The reviewed oil-fired equipment is identified according to the specific model's combustion design.
Heat Exchanger Design
NTI emphasizes engineered heat exchanger designs intended to maximize heat transfer and equipment longevity.
Venting Options
Venting requirements vary by model and combustion configuration.
Warranty
NTI warranty coverage depends upon the model and installation conditions.
Controls
Modern electronic controls are used on many NTI hydronic heating products.
Serviceability
Professional installation and service are recommended because of the equipment's control and combustion technology.
NTI Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Engineering emphasis, efficient hydronic heating design, and
modern control technology.
Trade-offs: Availability and technician familiarity vary significantly by
market.
Peerless
★★★★☆Peerless manufactures a range of residential oil-fired boilers using cast iron sectional heat exchangers. The brand has a long history in hydronic heating and is well known among heating contractors. Peerless oil boilers provide conventional reliability, serviceability, and strong warranty support on selected models.
AFUE Efficiency
Peerless oil boiler models generally operate in the mid-80% AFUE range, with exact performance varying by series.
Condensing vs Non-Condensing
The reviewed Peerless oil-fired boilers are conventional non-condensing units.
Heat Exchanger Design
Cast iron sectional construction provides durability and proven thermal performance.
Venting Options
Conventional chimney venting is used on many models, with venting options determined by the individual boiler.
Warranty
Selected Peerless models include substantial limited warranties on cast iron heat exchangers.
Controls
Conventional oil burner and operating controls provide reliable hydronic operation.
Serviceability
Peerless boilers use familiar construction that heating technicians can readily inspect, clean, and service.
Peerless Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Proven cast iron construction, established heating contractor
familiarity, and strong long-term serviceability.
Trade-offs: Non-condensing operation and conventional control technology.
Pennco
★★★☆☆Pennco manufactures conventional residential heating equipment, including oil-fired boilers. Its products emphasize straightforward cast iron construction, conventional burner operation, and serviceability. Pennco can be a reasonable budget-oriented choice when supported by a qualified local heating contractor.
AFUE Efficiency
Pennco oil boilers provide conventional mid-80% AFUE efficiency depending on the model.
Condensing vs Non-Condensing
The reviewed Pennco oil boilers are non-condensing.
Heat Exchanger Design
Cast iron sectional construction provides durable heat transfer and long-term operation.
Venting Options
Traditional venting arrangements are used on the reviewed equipment.
Warranty
Warranty coverage varies by model and includes heat exchanger and component provisions.
Controls
Conventional operating controls provide simple and serviceable boiler operation.
Serviceability
The straightforward boiler design is familiar to many heating technicians and supports routine maintenance.
Pennco Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Straightforward cast iron construction and conventional service
procedures.
Trade-offs: Fewer advanced features and more limited distribution than premium
brands.
Solaia
★★★★☆Solaia oil-fired boilers are designed around efficient three-pass cast iron heat exchanger technology. The boilers are intended for residential hydronic applications and emphasize fuel efficiency, durable construction, and service access. Solaia is a strong option for homeowners seeking a high-quality conventional oil boiler when local dealer support is available.
AFUE Efficiency
Solaia oil boiler models can provide efficiency in the upper 80% AFUE range, depending on the configuration.
Condensing vs Non-Condensing
Solaia boilers use conventional non-condensing oil-fired technology.
Heat Exchanger Design
Three-pass cast iron heat exchanger construction is designed to improve heat transfer and reduce wasted stack heat.
Venting Options
Venting requirements depend on the model and installation arrangement.
Warranty
Warranty coverage includes substantial protection for the cast iron heat exchanger on qualifying models.
Controls
Conventional burner and operating controls provide reliable operation.
Serviceability
Service-friendly construction allows technicians to access combustion and heat transfer areas for annual maintenance.
Solaia Oil Fired Boiler Model Comparison
Premium Series: Solaia
Why choose it: Three-pass cast iron heat exchanger, high conventional
efficiency, durable construction, and good service access.
Trade-offs: Non-condensing technology and a distribution network that is more
limited than the largest national brands.
Energy Kinetics System 2000
★★★★★Energy Kinetics' System 2000 is one of the most distinctive oil-fired heating systems available. Its design separates the boiler from the heat delivery controls and uses a highly efficient heat exchanger and thermal purge strategy to reduce standby losses. The System 2000 is known for very high seasonal efficiency, integrated domestic hot water capability, and excellent serviceability. It is a premium oil heating system and a top choice when the installation is properly designed and supported.
AFUE Efficiency
The System 2000 is designed to achieve very high seasonal efficiency through low standby losses, efficient heat transfer, and thermal purge operation.
Condensing vs Non-Condensing
The System 2000 uses a non-condensing heat exchanger design while achieving high system efficiency through its control strategy.
Heat Exchanger Design
The proprietary heat exchanger design is engineered for rapid heat transfer and low standby losses.
Venting Options
Venting options depend on the installation configuration and system model.
Warranty
Energy Kinetics provides substantial warranty coverage on qualifying boiler components, subject to published terms.
Controls
The Energy Manager control system manages burner operation, circulators, thermal purge, and domestic hot water production to reduce unnecessary burner cycles.
Serviceability
The system is designed around technician access to the burner, heat exchanger, controls, and other service components.
Energy Kinetics Oil Fired Boiler Model Comparison
Premium Series: System 2000
Why choose it: Exceptional system efficiency, thermal purge technology,
integrated domestic hot water production, sophisticated controls, and excellent standby-loss
performance.
Trade-offs: Higher purchase cost, proprietary components, and a requirement for
trained dealer/service support.
Thermo Dynamics
★★★☆☆Thermo Dynamics manufactures oil-fired boilers designed for residential hydronic heating. The equipment uses conventional cast iron construction and oil burner technology. Its products can provide dependable performance when installed and maintained by a qualified local heating contractor.
AFUE Efficiency
Thermo Dynamics oil boiler efficiency varies by model and generally falls within the conventional oil boiler range.
Condensing vs Non-Condensing
The reviewed Thermo Dynamics boilers use non-condensing technology.
Heat Exchanger Design
Cast iron construction provides durable heat transfer and long operating life.
Venting Options
Venting depends on the specific model and installation configuration.
Warranty
Warranty coverage varies by model and applicable manufacturer terms.
Controls
Conventional burner and operating controls are used.
Serviceability
Traditional construction provides familiar access for cleaning and maintenance.
Thermo Dynamics Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Conventional cast iron construction and straightforward service
procedures.
Trade-offs: Dealer and parts availability should be verified before purchase.
Thermoflo
★★★★☆Thermoflo offers residential oil-fired boilers with an emphasis on durable cast iron construction and efficient heat transfer. The brand's products are designed for conventional hydronic systems and are generally distributed through heating professionals. Thermoflo can be a strong option when local service support is available.
AFUE Efficiency
Thermoflo oil boiler efficiency varies by model, with selected models providing strong performance for conventional oil-fired technology.
Condensing vs Non-Condensing
The reviewed Thermoflo oil boilers use non-condensing technology.
Heat Exchanger Design
Durable cast iron heat exchanger construction is used for reliable heat transfer and long service life.
Venting Options
Venting requirements depend on the individual model and installation.
Warranty
Thermoflo provides warranty protection according to the applicable model and installation terms.
Controls
Conventional burner and boiler controls provide reliable operation.
Serviceability
Service-friendly construction allows technicians to perform routine cleaning and maintenance.
Thermoflo Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Durable cast iron construction, efficient heat transfer, and
straightforward service.
Trade-offs: Local distribution and contractor availability are important
considerations.
TRIO
★★★★☆TRIO oil-fired boilers are designed around three-pass cast iron heat exchanger technology and efficient conventional oil combustion. The three-pass design extracts additional heat from combustion gases while maintaining a straightforward non-condensing architecture. TRIO products are well suited to homeowners seeking a durable and efficient conventional oil boiler.
AFUE Efficiency
TRIO oil boilers can provide efficiency in the upper 80% AFUE range depending on model and burner configuration.
Condensing vs Non-Condensing
TRIO boilers use non-condensing technology.
Heat Exchanger Design
The three-pass cast iron heat exchanger is designed to maximize heat transfer before combustion gases leave the boiler.
Venting Options
Venting requirements depend on the model and installation configuration.
Warranty
Warranty coverage includes protection for the cast iron heat exchanger and other components according to the applicable terms.
Controls
Conventional burner and operating controls are used for reliable hydronic heating operation.
Serviceability
The boiler design provides straightforward access for annual cleaning and technician service.
TRIO Oil Fired Boiler Model Comparison
Premium Series: TRIO
Why choose it: Three-pass cast iron heat exchanger, strong efficiency, durable
construction, and straightforward serviceability.
Trade-offs: Non-condensing technology and professional dealer distribution.
U.S. Boiler
★★★★☆U.S. Boiler Company manufactures a broad range of residential heating equipment, including several oil-fired boiler series. Its oil boilers are known for cast iron construction, conventional serviceability, and a wide range of configurations for hot water and steam systems. U.S. Boiler benefits from an extensive professional heating distribution network and strong contractor familiarity.
AFUE Efficiency
U.S. Boiler oil-fired models range from conventional efficiency designs to higher-efficiency three-pass configurations, depending on the series.
Condensing vs Non-Condensing
The reviewed U.S. Boiler oil equipment is primarily non-condensing.
Heat Exchanger Design
Cast iron sectional heat exchangers provide durability and reliable thermal performance, with premium models using multi-pass designs.
Venting Options
Venting options vary by series and may include conventional chimney or other approved configurations.
Warranty
U.S. Boiler provides substantial limited warranty coverage on qualifying cast iron heat exchangers.
Controls
Conventional burner and operating controls are used, with optional system controls available on selected equipment.
Serviceability
U.S. Boiler products are widely recognized by heating technicians and are designed for conventional cleaning and service access.
U.S. Boiler Oil Fired Boiler Model Comparison
Premium Series: MPO-IQ
Why choose it: Three-pass cast iron heat exchanger, high efficiency for a
conventional oil boiler, advanced IQ control platform, and strong serviceability.
Trade-offs: Higher initial cost and professional distribution.
Basic Series: V8 / V8H
Why choose it: Proven cast iron construction, straightforward controls, broad
contractor familiarity, and multiple hot water/steam configurations.
Trade-offs: Lower efficiency than premium three-pass models and fewer advanced
controls.
Utica
★★★☆☆Utica Boilers manufactures conventional residential oil-fired boilers using cast iron heat exchangers. The brand offers a range of models for hot water and steam applications and benefits from established HVAC distribution. Utica is a practical choice for homeowners seeking conventional boiler technology and local contractor support.
AFUE Efficiency
Utica oil boilers provide conventional efficiency, with model-specific AFUE ratings varying by series.
Condensing vs Non-Condensing
The reviewed Utica oil-fired boilers use non-condensing technology.
Heat Exchanger Design
Cast iron sectional heat exchangers provide durability and established hydronic heating performance.
Venting Options
Conventional venting configurations are available depending on model and installation requirements.
Warranty
Warranty coverage varies by series, with substantial heat exchanger protection on qualifying models.
Controls
Conventional oil burner and boiler controls are used for straightforward operation.
Serviceability
Familiar construction makes annual cleaning, burner service, and inspection straightforward for qualified technicians.
Utica Oil Fired Boiler Model Comparison
Residential Oil Boiler
Why choose it: Conventional cast iron construction, broad product selection,
and established contractor support.
Trade-offs: Conventional efficiency and fewer advanced controls than premium
systems.
Viessmann
★★★★☆Viessmann is known internationally for advanced heating technology and high-quality boiler engineering. Its oil-fired products emphasize efficient combustion, sophisticated heat exchanger design, and strong system integration. Viessmann can be an excellent choice where its oil products and trained dealer network are available.
AFUE Efficiency
Viessmann oil boiler efficiency varies by model, with selected products achieving high efficiency for conventional oil-fired equipment.
Condensing vs Non-Condensing
Viessmann offers both conventional and advanced combustion technologies depending on the product line.
Heat Exchanger Design
Viessmann's engineering emphasizes optimized heat transfer, durable materials, and efficient boiler operation.
Venting Options
Venting requirements depend on the model and combustion design.
Warranty
Warranty coverage varies by model and market and should be confirmed with the installing dealer.
Controls
Advanced electronic controls and system integration are available on selected Viessmann equipment.
Serviceability
Viessmann equipment benefits from professional dealer service and manufacturer-specific training.
Viessmann Oil Fired Boiler Model Comparison
Premium Residential Oil Boiler
Why choose it: Advanced engineering, efficient heat transfer, sophisticated
controls, and high-quality construction.
Trade-offs: Higher purchase cost and the need for trained dealer support.
Weil-McLain
★★★★☆Weil-McLain manufactures a broad selection of oil-fired boilers for residential hot water and steam heating. The brand's products include conventional cast iron boilers as well as higher-efficiency three-pass designs. Weil-McLain has a large professional distribution network and strong contractor familiarity, making it one of the more widely supported oil boiler brands.
AFUE Efficiency
Weil-McLain oil boiler efficiency varies by model, with premium models reaching the upper 80% AFUE range.
Condensing vs Non-Condensing
Most residential oil models utilize traditional non-condensing technology engineered for safe, high-temperature operating loops and conventional flue gas temperatures.
Heat Exchanger Design
Built with commercial-grade, heavy-duty cast iron sectionals featuring advanced three-pass configurations on premium models for superior heat absorption and longevity.
Venting Options
Provides versatile installation flexibility supporting conventional chimney venting as well as direct-vent sidewall options on select series.
Warranty
Backed by a 20-year limited warranty on the cast iron heat exchanger and a 2-year limited warranty covering electrical parts and controls for residential installations.
Controls
Equipped with protected, top-mounted hinged control pods featuring integrated operating limits, pressure gauges, and optional low water cut-off protection.
Serviceability
Engineered with technician-friendly access including reversible full-swing burner doors that expose the entire combustion chamber and flueways for easy annual cleaning.
Weil-McLain Oil Fired Boiler Model Comparison
Premium Series: Ultra Oil
Why choose it: Commercial-grade three-pass cast iron heat exchanger achieving
87% AFUE, sleek appliance-like jacket design, direct-vent flexibility, B100 biodiesel readiness,
and a reversible full-swing service door.
Trade-offs: Non-condensing technology, floor-standing footprint, and
distribution restricted to professional heating contractors.
Basic Series: WGO / WTGO / SGO Series 4
Why choose it: Proven cast iron sectional design, reliable steam (SGO) or water
(WGO/WTGO) operation with optional tankless domestic hot water coils, B100 compatibility, and
robust 20-year heat exchanger warranty.
Trade-offs: Conventional chimney venting requirements, basic single-stage
control operation, and non-condensing efficiency limitations.
Williamson
★☆☆☆☆Williamson offers residential oil-fired boilers manufactured in the USA, featuring the heating-only OWB series and the OWT series with an integrated domestic hot water coil. Delivering an 86% AFUE efficiency rating, these floor-mounted cast iron units utilize conventional chimney venting and swing-open burner doors for simplified cleaning. While offering optional two-stage burners and rugged construction, the brand suffers from a very limited dealer distribution network and a pro-rated 20-year heat exchanger warranty with minimal electrical parts coverage, yielding a below-average overall value proposition.
AFUE Efficiency
Williamson oil boilers achieve an 86% AFUE efficiency rating, meeting baseline standards for non-condensing residential hydronic heating systems.
Condensing vs Non-Condensing
All models in the Williamson residential oil lineup feature standard non-condensing operation designed for traditional high-temperature hydronic loops.
Heat Exchanger Design
Constructed with durable cast iron sectionals engineered for reliable thermal transfer and long operational service life.
Venting Options
Designed for traditional conventional chimney venting applications in residential installations.
Warranty
Backed by a 20-year pro-rated limited warranty on the cast iron heat exchanger alongside a 1-year limited warranty covering electrical components and controls.
Controls
Equipped with basic electromechanical operating and safety limit controls without factory-integrated modulating or outdoor reset functionality.
Serviceability
Features a swing-open burner door design that allows technicians straightforward access for annual cleaning, inspection, and maintenance.
Williamson Oil Fired Boiler Model Comparison
Basic Series: OWB / OWT
Why choose it: Rugged cast iron sectional construction, 86% AFUE efficiency,
optional two-stage burner capability, swing-open burner door for easy maintenance, and an
integrated domestic hot water coil on the OWT model.
Trade-offs: Non-condensing technology, conventional chimney venting
requirement, pro-rated heat exchanger warranty structure, short 1-year electrical parts
warranty, and very limited dealer availability.
Frequently Asked Questions: Oil Fired Boiler Ratings
What AFUE information is included?
Each oil-fired boiler review identifies the AFUE efficiency of the reviewed equipment where provided.
Are these boilers condensing or non-condensing?
The individual brand reviews identify the condensing or non-condensing design of the reviewed oil-fired boilers.
What warranty information can I compare?
The Head To Head tool compares parts and heat exchanger warranty information for the selected boilers.
Can I compare two boilers side by side?
Yes. Select Brand 1 and Brand 2 in the Head To Head Comparison Tool to compare the available specifications.
Is a dealer required?
Dealer requirements are included as a comparison field in the Head To Head tool and in individual reviews where provided.
Meet the Expert: HVAC Repair Guy (Richard Reed)
HVAC Specialist & Founder of HVAC For Beginners
Richard Reed brings over 17 years of specialized HVAC industry experience. His unique background includes serving as an electrician in nuclear power before completing a 4-year HVAC service apprenticeship and 8 years of field experience. Based in the Midwest, he has helped homeowners understand, maintain, and upgrade their systems since the early 2000s. His mission is to provide unbiased, “repairman’s point of view” insights into energy conservation and alternative energy solutions.